All languages do have rules which are called grammar. These rules are necessary to enable those who are learning the language to be able to continue to grow their vocabulary and speak in long sentences throughout their lifetime.
If rules did not exist in language acquisition, the student would find it a huge effort to learn a new language because then they would have to learn each sentence separately. The rules define how sentences should be constructed and what is right from what is the wrong way to put a sentence together. Using those rules helps the student to know how and when to use certain words, verbs, nouns and phrases in a sentence.
With those rules in place, the student will feel more confident in combining words into sentences and can create myriads of sentences on their own while administering these rules of language. The person who has knowledge of the syntax will see the sentence as more meaningful to them. Syntax is very important in constructing sentences and once the rules are learned, it comes quite naturally to the speaker.
In terms of language acquisition, Syntax is the study pertaining to the sentence construction rules and principles in a native language. It goes to the reference of the rules governing the structure of sentences in any language. There are some generic rules that apply to all languages as it relates to its syntax.
The rules include things such as how words are put together, how the word ending changes as it relates to the context of the sentence and how the parts of speech are connected.
In language acquisition, syntax in sentences is exemplified by a few methods below:
“The girl caught the ball”
Here is how you would describe the syntax rule of any sentence (noun or subject is followed by verb and then verb is followed by object or noun): In the above sentence, the subject is the girl and that is followed by the verb caught and then another noun which is the ball.
It does not matter how complex the sentence is because words can be embedded into the existing sentence to make the rules of syntax still work and still meaningful.